From a2ce57d856c299ac5cebf6b0ddc11ad8b7906a12 Mon Sep 17 00:00:00 2001
From: Doug Coleman <doug.coleman@gmail.com>
Date: Wed, 3 Feb 2010 17:20:24 -0600
Subject: [PATCH] Allow setting errno instead of just clearing it

---
 basis/libc/libc.factor | 8 +++++++-
 vm/io.cpp              | 4 ++--
 vm/io.hpp              | 2 +-
 3 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/basis/libc/libc.factor b/basis/libc/libc.factor
index fe56c83516..e935d49748 100644
--- a/basis/libc/libc.factor
+++ b/basis/libc/libc.factor
@@ -9,8 +9,14 @@ IN: libc
 : errno ( -- int )
     int "factor" "err_no" { } alien-invoke ;
 
+: set-errno ( int -- )
+    void "factor" "set_err_no" { int } alien-invoke ;
+
 : clear-errno ( -- )
-    void "factor" "clear_err_no" { } alien-invoke ;
+    0 set-errno ;
+
+: preserve-errno ( quot -- )
+    errno [ call ] dip set-errno ; inline
 
 <PRIVATE
 
diff --git a/vm/io.cpp b/vm/io.cpp
index a3283b84ac..880675b212 100755
--- a/vm/io.cpp
+++ b/vm/io.cpp
@@ -245,8 +245,8 @@ VM_C_API int err_no()
 	return errno;
 }
 
-VM_C_API void clear_err_no()
+VM_C_API void set_err_no(int err)
 {
-	errno = 0;
+	errno = err;
 }
 }
diff --git a/vm/io.hpp b/vm/io.hpp
index 41e9cec82d..c96c95863d 100755
--- a/vm/io.hpp
+++ b/vm/io.hpp
@@ -8,6 +8,6 @@ int safe_fclose(FILE *stream);
 /* Platform specific primitives */
 
 VM_C_API int err_no();
-VM_C_API void clear_err_no();
+VM_C_API void set_err_no(int err);
 
 }